Add test case for reset group snapshot status

Reset group snapshot status is a new api implemented in v3 group snapshots,
min_microversion is 3.19. This patch adds test case for this new feature.

Including:

[1] Add reset group snapshot status api to v3 group_snapshots_client
[2] Add unit test for reset group snapshot status api
[3] Add test case: test_reset_group_snapshot_status
[4] Add release note

Change-Id: I14f5b8fd0f386ea5f84cc3a2decede430a7e7893
4 files changed